The present invention relates generally to power amplifiers, and more particularly, to a miniature broadband linearizer for use with power amplifiers.
Heretofore, Lockheed Martin Corporation has developed a broadband linearizer that is implemented using passive FET technology. This broadband linearizer is discussed in a paper entitled "MMIC Linearizers for C and Ku-Band Satellite Applications", by R. Dorval, published in 1998 IEEE MTT-S International Microwave Symposium Workshop".
Nippon Electric Company (NEC) manufactures linearizers for use with power amplifiers. Such linearizers are disclosed in a report entitled "INTELSAT-VII Linearizer for Ku-Band TWTA", and a "Linearizer for Ku-Band TWTA Performance Specification" (Specification No. E021307). The NEC linearizers use commandable switched frequency bands to cover a wide bandwidth. However, the basic design for each band of the NEC linearizers are narrow band. Also, the NEC linearizers use FET amplifiers as nonlinear elements.
Alcatel has developed a linearized channel amplifier that uses a MMIC amplifier as a nonlinear element.
AEG (Daimler-Benz AG) has developed a linearizer preamplifier that includes a nonlinear Schottky diode circuit, a phase shifter and three MMIC amplifiers. This preamplifier is disclosed in a paper entitled "Pseudomorphic Ku-Band GaAs HFET Linearizer Preamplifier Front End for Satellite TWT-Amplifiers", published in the 1995 IEEE GaAs IC Symposium.
In general, however, these conventional linearizers also do not provide for a simple, compact low cost design that does not involve complex commandable switched band selection operation.
Accordingly, it would be advantageous to have a broadband linearizer that may be used with a power amplifier to improve the linearity and efficiency performance of the power amplifier across a wide frequency bandwidth.